As part of a multiyear program to promote development, the City of Milwaukee is spending $16 million this year to repave 30 miles of streets. Several years ago, the city began installing galvanized-steel adjustable manhole risers instead of cast iron risers in mill-and-fill operations.
Scott Fier As part of a multiyear program to promote development, the City of Milwaukee is spending $16 million this year to repave 30 miles of streets. Several years ago, the city began installing galvanized-steel adjustable manhole risers instead of cast iron risers in mill-and-fill operations.

“We were having problems with cast iron manhole risers,” says City of Milwaukee Engineer in Charge Samir Amin, PE. “They’re usually fine, but on occasion they’d slip or rattle out, and that led to car damage and claims. There was definitely room for improvement.”

About five years ago, Amin was approached by a representative from American Highway Products of Bolivar, Ohio, who demonstrated the company’s pivoted turnbuckle manhole riser. The adjustable riser is galvanized steel, precisely sized to order, that features a turnbuckle. Using a screwdriver as a lever, the turnbuckle transmits thousands of pounds of force to the flexible rim, seating the riser into original utility rim securely. Installation typically takes five minutes or less. Unlike risers that depend on set screws or other mechanisms for adjustment, the pivoted turnbuckle riser connects tightly around its entire circumference, like a pressed-in bearing.

It seemed like a good idea to Amin, so he organized a pilot project.

“We picked a street near our municipal yards that sees a lot of heavy truck traffic,” he says. “We set several there and just watched over time. There were no failures or slips, so we were convinced they’d work better than the non-adjustable risers.”

The city couldn’t specify a particular brand of riser. Instead, Milwaukee wrote specifications for riser use that required adjustable risers with a mechanism similar to the pivoted turnbuckle.

“At the very beginning we faced some resistance from contractors, who were used to the readily available cast iron risers,” Amin says. “But that went away quickly, and now nobody mentions it.” City crews also install the risers, including the company’s catch basin risers, and keep about a hundred in inventory for use as needed.

Unlike risers that depend on screws or other mechanisms for adjustment, the pivoted turnbuckle riser connects tightly around its entire circumference, like a pressed-in bearing. One person using a screwdriver can install the lightweight riser.
Scott Fier Unlike risers that depend on screws or other mechanisms for adjustment, the pivoted turnbuckle riser connects tightly around its entire circumference, like a pressed-in bearing. One person using a screwdriver can install the lightweight riser.

“Risers aren’t a big item in most of our mill-and-fill bids, and I didn’t notice any significant increase in costs due to the required use of adjustable risers,” says Amin.

By now, the city’s installed close to a thousand. Milwaukee has emphasized milling and repaving in recent years, and Amin estimates that 200 to 300 risers are installed annually. None have rattled out or failed in any way.

“We’re very happy with them,” says Amin. “They cost a bit more compared to cast iron risers, but we have no worries about them coming loose and that means a lot.”